Chicago used its mini mid-level exception on the shooting specialist in hopes that he'd improve the team's outside shooting.
As the Chicago Sun-Times reported, Dunleavy took less money to join the team, saying that at this point in his career, "having a chance to win" is more important.
Dunleavy brings more than just perimeter and three-point shooting, though.
His size and well-rounded game gives the Bulls possibilities for various looks offensively and a chance to run some new sets.
Many would give Jimmy Butler the X-factor label, but both players have equal potential to considerably boost the team's offense and increase efficiency. Also, Butler still has to prove himself while Dunleavy is an established weapon.
So why is Dunleavy the Bulls' X-factor?
Dunleavy shot a career-high 42.8 percent from downtown last season, which would have been the highest on the Bulls' 2012-13 roster.
His sharpshooting skills are sure to help enhance the Bulls offense if he can consistently get good looks.
Derrick Rose is sure to help in that regard as his dribble penetration will draw in extra defenders. The 11-year veteran spoke with Aggrey Sam of CSN Chicago about how he'd benefit from playing with the former MVP.
With him, he’s just such a dynamic player. He makes so many plays for himself and others. You’ve just got to make sure you’re in the right position, ready to shoot or ready to make a play because each and every time down the court, he’s got a chance to do something unique.
After ranking 20th with a 35.3 three-point shooting percentage, Chicago is sure to benefit from Dunleavy's presence.
At 6'9", 220 pounds, Dunleavy allows the Bulls to try multiple offensive lineups.
After the Bulls' Sept. 28 practice, Tom Thibodeau told the media that Dunleavy was capable of playing in a lineup full of swingmen, per CSN Chicago's report. "We saw [in the practice] that Mike can play with Jimmy [Butler], he can play with [Luol Deng]. Then, you can slide Mike, Jimmy and Luol to the four if you wanted to."
Dunleavy agreed with that notion, saying he believes the Bulls' versatility will help them cover up some of their depth issues at the wing positions.
The Bulls can also counter teams that like to use small ball sets. As Bulls' insider Aggrey Sam pointed out, the former Blue Devil's skill set allows him to stay on the floor—despite his larger size—and exploit matchups.
If Thibodeau were to use Dunleavy as a stretch 4, he could open up things for Rose and even Butler to work inside. It also gives the Bulls a chance to run some pick-and-pop sets, giving Dunleavy a chance to shoot or even drive against a slower power forward.
Chicago can experiment with Dunleavy during the preseason, and if successful, it wouldn't be a surprise if he played three different positions throughout the regular season.
Most might see Dunleavy as nothing more than a shooter, but Thibodeau believes the 33-year-old sharpshooter will affect the game in more than one way.
[Dunleavy] had a very good practice, moved very well without the ball and passed the ball well, and of course shooting... Anytime you add a guy that can pass the ball like that it helps make everyone better. The transition right now is going very well, he’s got to continue to work, but I like the versatility.
Dunleavy's gotten some Kyle Korver comparisons, but as Thibodeau explained, he's a more complete player.
Who is the Bulls' X-factor for 2013-14?
Aside from his off-ball movement and his passing skills, he's also capable of putting the ball on the floor, something Korver wasn't very good at.
This gives him a chance to put the ball on the floor and pull up or pass it off to the big for an inside bucket.
Chicago may have struck gold with its main free-agent signing. Dunleavy brings a lot of the things Marco Belinelli brought to the team, except that the former is a more efficient shooter.
Dunleavy could potentially be the new bench mob's best contributor, and if he can repeat last season's outing, Chicago will have put itself one step closer to the Larry O'Brien trophy.